Decalcomania for metal transfers



Jan. 13, 1953 D. D. SWIFII' ET AL 2,625,496

DECALCOMANIA FOR METAI; TRANSFERS Filed Sept. 30, 1950 GOLD LEAF WATERSOLUBLE GUM PA PER INVEN TOR. DONALD D. SWIFT Q BY JaH/v 1K0 LERATTORNEY Patented Jan. 13, 1953 DECALCOMANIA FOR METAL TRANSFERS DonaldD. Swift, West Hartford, and John J. j Kohler, Hartford, Conn.,assignors to M. Swift & Sons, Inc., Hartford, Conn., a corporation ofConnecticut Application September 30, 1950, Serial No. 187,841

. 1 I The invention relate to decalcomanias and their manufacture.

Summary According to our invention, decalcomanias for applying metaldecorations to articles, either as continuous or all over coatings, orin the form of designs, patterns or lettering, comprise a paper transfersheet and metal foil held together with an adhesive comprising awater-soluble gum and a butadiene-acrylonitrile polymer. Morespecifically our decalcomania comprises a composite of the followinglayers of material arranged in the order stated: (1) a paper transfersheet, (2) a water-soluble adhesive, (3) a butadieneacrylonitrilepolymer, (4) metal foil. The metal foil may for example be gold, tin,copper, aluminum, or alloys of these or other metals.

A special application of the invention which has shown considerablepromise is a decal for gilding. This decal comprises a paper transfersheet and gold leaf held together with an adhesive comprising awater-soluble gum and a butadiene-acrylonitrile polymer, or comprises acomposite of the following layers of material: (1) a paper transfersheet, (2) a water-soluble adhesive, (3) a butadiene-acrylonitrilepolymer, (4) gold leaf (or gold leaf design).

In one form of the invention there is a layer of lacquer between thebutadiene polymer and the metal foil.

The method of making the metal decal preferably comprises applying acoating of butadieneacrylonitrile polymer to the metal surface of acomposite metal foil transfer sheet comprising metal foil carried on atransfer sheet such as provided by a cellulose acetate backing, andapplying a coating of butadiene-acrylonitrile polymer to a compositepaper transfer sheet comprising a water-absorbent paper coated with awatersoluble adhesive, pressing the two composite sheets together withthe butadiene-acrylonitrile coatings in juxtaposition to adhere themetal foil transfer sheet to the paper-transfer sheet, and afteradherence is obtained, removingthe transfer portion or cellulose acetatebacking of the metal foil transfer sheet to produce a decalcomaniacomprising the layers of material as described above.

In the drawing the figure is a perspective view of a portion of adecalcomania formed in accordance with our invention and comprising acomposite of the following layers of material in the order stated: apaper transfer sheet, a water 6 Claims. (01. 154-463) soluble gum, abutadiene-acrylonitrile polymer, and gold leaf or other metal foil.

Description Decalcomanias, or decals as they are sometimes called forshort, are made ordinarily by printing designs on paper coated with awater-soluble adhesive. When the decal is moistened the coating softensand permits separation of the printed design from the surface of thepaper either by sliding off the transfer by pulling the paper fromunderneath it, or in the case of direct transfers where an adhesive isapplied over the surface of the printing, the decal is moistened andpressed against the surface to which the transfer is to be applied andthe paper is slid from the top of the transfer instead of from thebottom. Direct transfers are printed in reverse when they are to beapplied to opaque surfaces or to the outside of Windows, but are printedright side up when they are to be applied to the inside of windows or ofa transparent object where the design or' lettering is to be viewedthrough the glass.

In another type of decal known as a varnish transfer a coat of lacqueror varnish is stenciled on the paper before printing, and after printinganother coat of lacquer or varnish is stenciled over the printing. Inapplying this type of decal, varnish is applied either to the transferor to the surface to which it is to be affixed, and after the varnishbecomes tacky the decal is applied and smoothed out with a squeegee orsoft cloth. After drying, the paper is peeled off.

Our invention is applicable to all of these types of transfers. That is,decals made in accordance with our invention can be used either asslide-off transfers, direct transfers or varnish transfers. Also it isto be understood that the terms decalcomania or decal as used hereininclude plainor solid colors as well as designs and lettering. In factour invention is especially suited to the gilding or metalizing ofsurfaces with metal leaf to produce a solid or all-over coating capableof stretching into intimate contact with the surface irregularities ofconfigurations of the object to which the decal is applied. Thus thecharacteristics of our product render it particularly well adapted tothe transfer of metal foils to surfaces having designs in eitherintaglio or relief.

' Our decals comprise a paper transfer sheet coated in succession with awater-soluble adhesive, a butadiene-acrylonitrile polymer and metalfoil. There may be a layer of lacquer between the butadiene polymer andthe metal foil, and

althdugh this is not necessary in the case of a direct transfer it maybe desirable in the case of a slide-off transfer. The decal paperemployed may be one of the types available on the market today, forexample either a simplex paper or lithotransfer paper which are incommon use. The simplex paper comprises a smooth book paper coated witha water-soluble adhesive. The lithotransfer paper consists of papercoated first with a watch-soluble adhesive and then with lactruer. Thewater-soluble adhesive may be starch, gum arable, gum tragacanth,dextrin, gelatin or mixtures of the same, or may consist of a syntheticorganic compound such as hydroxyethyl cellulose, carboxymethyl celluloseor polyvinyl alcohol which are soluble in water and have adhesiveproperties. We prefer the mixture of starch and gum arabic in the usualproportions as commonly employed in the production of ordinary decalpapers.

Starting with a conventional dec'al paper, we first apply a coating of abutadiene-acrylonitrile polymer or its natural or synthetic equivalentin a suitable solvent such as methyl ethyl ketone, by spraying, rollercoating or otherwise. Such solutions are generally known as buna-Nsolutions, buna-N being essentially a buta-diene-acrylonitrile polymer.The butadiene-acrylonitrile solution used generally is modified with asmall percentage of a phenolic resin. Alternatively such a solution maybe sprayed on the metal surface of a composite metal foil transfer sheetconsisting of metal foil adhered to a cellulose acetate backing by afilm of wax or the like. We have found that the best results areobtained if the buna-N solution is sprayed both on the decal paper andthe metal composite.

Following the application of the buna-N solution, the compositepapertrans'fe sheet and composite metal foil transfer sheet are pressedtogether, and after adherence is obtained the cellulose acetate transferportion of the metal foil transfer sheet is removed.

We have found that optimum results are obtained with a buna-N filmthickness of between 0.000% to 0.0007 gram per square inch. It ispreferableto apply approximately one-half of the total film thickness onthe metal foil and the other half on the decal paper, but if desired abima-N film of between 0.0004 to 0.0007 gram Per Square inch can beapplied entirely to the metal foil surface alone or to the decal papersurface alone.

The paper foil composites can be'brou'ght together two or three minutesafter the buna-N film has been applied. However the length of timebetween application of the filth and pressing does not appear to becritical, as we have found for example that the two composites can bebrought together at least as long as 43 hours after application. Weprefer to bring the two composites together between 4 and 5 hours aftercoating, and thisprocedure has been found to produce optimum results inmost cases.

Reference has been made to the metal foil composite consisting of a foiladhered to a cellulose acetatebacking'by means of a film of wax or thelike. The method of manufacturing such composites is well known andforms no part of the present invention, and the composites are availableon the market today as copper foil transfers, gold leaf transfers, etc.,these being the type of transfers which are employed in applyinggoldleaf, silverleaf, aluminum-foil, copper foil. etc. to the shelf backsand covers of books, and to leather goods and other objects with the useof hot stamping dies. Other metal foil composites may be used,specifically nickel foil, a 14 karat gold-tin alloy, and a 20 karatgold-tin alloy, for example. The metal foils or leaf, and moreparticularly the gold leaf, may range in thickness from one to sixmilliontlis of an inch, generally averaging between two and threemillionths of an inch.

From the foregoing description the manufacturer or artisan willunderstand how to select or make up the decal paper, and he will ofcourse make his selection of the metal foil transfer according to thekind of decal he wishes to make. Also we have taught him to apply abuna-N type film either to the adhesive or lacque coated surface of thepaper or metal surface of the metal foil transfer, and preferably toboth such surfaces, and how thick this film or these films should be.Finally we have shown how the two composite sheets are brought togetherand pressed into adhering relationship. As to this last procedure wehave found that it is convenient to stack a number of pairs of thecomposite sheets in a pile in a press. No heat is applied during thepressing operation. All that the operator need do is spin down the wheelof the press and bring it up tight as would be done in ordinaryletterpress or bookbinding operations, and the like. If desired, amechanical o hydraulic press may be employed. Fifteen to thirty minuteslater the decals will be ready to be removed from the press, and the twocomposite sheets of each pair will be found to be firmly united by thelbuna-N film. However the length of time the sheets are left in thepress is not critical. Grdinarily the workman willprepare the stacks forthe presses during the day, and shortly before quitting time he willclamp the stacks in the presses and leave them overnight for removal thefollowing morning when he-starts work. However this procedure is ofcourse entirelyoptional.

Following removal of the cellulose acetate film the decal is ready fouse; except in those cases where it is intended for application bydirect transfer face down on an unsized surface, in which event a thincoating of a suitable water soluble adhesive is applied to the metalsurface of the decal by-spraying or roller coating. This adhesive maybeany of those previously described with reference to the coated decalpaper.

By way of further exemplification, we cite the following specificexamples of :the practice of our invention:

1. A24 K gold fo'ilof tw'o millionths of an inch in thickness on acellulose acetate carrier was coated with abutadiene acrylonitrile filmof 0.0003 gram per square inch in thickness. A sheet of paper which hadbeen previously sized with a water soluble gumwas also coated with abutadiene acrylor'iitrile mm of 0.0003 gm. per square inch. Both coatedsurfaces were allowed to dry forten minutes and then brought togetherwith the fauna-N surfaces contacting each other. This assembly wasplaced in a press and held there for fifteen minutes .at roomtemperature. At the end of the pressing period the cellulose acetatecarrier was removed. This left a composite consisting ofgold bonded tothe buna-N, which in turn was bonded to the water solublegurn coatedpaper.

2. A 24.K-go1d foil, three millionths of an inch thick and supported ona cellulose acetate carrier was made to contact a buna-N surface whichhad previously been coated to a thickness of 0.0006 gram per square inchon water soluble gum coated absorbent paper. The composite was placedinfa press for one half hour and then removed. The cellulose acetatecarrier was stripped from the composite, leaving the gold in adherencewith the buna-V surface on the water soluble gum ofthe absorbent paper.

3. An aluminum foil two millionths of an inc thick, supported on acellophane carrier, .was coated with buna-N to a film thickness of0.0007 gram per square inch. It was then brought in contact with a watersoluble, presized absorbent paper. The composite was placed in a pressfor twenty minutes, and on withdrawal from the press the cellophanecarrier was stripped free from the composite. The sheet was cut by handto shape for decorating a picture frame.

4. An absorbent paper which had previously been coated with a watersoluble gum and then coated with a cellulose nitrate lacquer wasthereafter coated with buna-N to a thickness of 0.0006 gram per squareinch. The buna-N surface was brought into contact with the surface of a24K gold foil two millionths of an inch thick supported on a celluloseacetate carrier. The composite was placed in a mechanical press forfifteen minutes. It was then withdrawn from the press, and the celluloseacetate carrier was stripped from the composite. The sheet of foil sopreparedwas L of surfaces to produce a solid or all-over coating capableof stretching into intimate contact with the surface irregularities ofthe object to be decorated. We have found that even where such surfacesare quite irregular as, for example, in a picture frame having a designmolded in intaglio i or relief, the decal is sufficiently flexible toconform with the irregularities of the surface. The metalleaf with itsbuna-N backing exhibits a certain degree of resiliency. It does not seemto be possible to achieve comparable results in the absence of the useof the butadiene-acrylonitrile polymer, for without this the metal leafbreaks up and shows cracks or fissures. However even with very thin goldleaf, when the metal is supported as we have described, it remainspermanently flexible. When subjected to tension it stretches in anall-over pattern as though each molecule of the metal were stretchedrather than in a pattern of normally visible cracks such as occur whenthin metal foil or leaf has been stretched beyond its ultimate strength.The explanation of the results attained in this regard is necessarilysomewhat theoretical, but in any event we have found that decals made inthe manner described produce excellent decorative 60 2,49 77 effects ona Wide variety of objects with either smooth or irregular surfaces.

Our decals can be used in a great many ways, that is by following any ofthe various techniques known to the art for the application of ordinarydecals.

The terms and expressions which we have employed are used in adescriptive and not a limiting sense, and we have no intention ofexcluding such equivalents of the invention described, or of portionsthereof, as fall within the purview of the claims.

We claim:

1. A decalcomania comprising a paper transfer sheet and metal foil heldtogether with an adhesive comprising a layer of water soluble gum and alayer of butadiene-acrylonitrile polymer.

2. A decalcomania comprising a composite of the following layers ofmaterial arranged in the order stated: (1) a paper transfer sheet, (2) aWater soluble adhesive, (3) a butadiene-acrylonitrile polymer, (4) metalfoil.

3. A decalcomania comprising a paper transfer sheet and gold leaf heldtogether with an adhesive comprising a layer of Water soluble gum and alayer of outadiene-acrylonitrile polymer.

4. A decalcomania comprising a composite of the following layers ofmaterial arranged in the order stated: (1) a paper transfer sheet, (2) awater soluble adhesive, (3) a butadiene-acrylonitrile polymer, (4) goldleaf.

5. A decalcomania comprising a composite of the following layers ofmaterial arranged in the order stated: (1) a paper transfer sheet, (2) awater soluble adhesive, (3) a butadiene-acrylonitrile polymer, (4)lacquer, (5) metal foil.

6. A decalcomania comprising a, composite of the following layers ofmaterial arranged in the order stated: (1) a paper transfer sheet, (2) awater soluble adhesive, (3) a butadiene-acrylonitrile polymer, (4)lacquer, (5) gold leaf.

DONALD D. SWIFT. JOHN J. KOI-ILER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,096,822 Brandt May 19, 19141,137,278 Peterson Apr. 27, 1915 1,213,926 McManus Jan. 30, 19171,376,737 Tscheike May 3, 1921 1,591,844 Kosai July 6, 1926 2,044,922Swift et al June 23, 1936 2,099,641 Bach et a1 Nov. 16, 1937 2,354,073Swift July 18, 1944 2,364,674 Swift Dec. 12, 1944 Chmiel Dec. 20, 1949

1. A DECALCOMANIA COMPRISING A PAPER TRANSFER SHEET AND METAL FOIL HELDTOGETHER WITH AN ADHESIVE COMPRISING A LAYER OF WATER SOLUBLE GUM AND ALAYER OF BUTADIENE-ACRYLONITRILE POLYMER.